1. Field of the Invention
The present invention relates to a numerical controller with a program resuming function, and more particularly, to a numerical controller that acquires program-resuming block data at a non-cutting position where a workpiece is not subject to cutting.
2. Description of Related Art
In a machine tool controlled by a numerical controller, it has heretofore been practiced to arbitrarily acquire program-resuming block data of a machining program from a current state of numerical control during workpiece machining. For example, a method for acquiring program-resuming block data for every predetermined blocks at regular intervals is disclosed in JP 2002-373008A.
The above conventional method for acquiring program-resuming block data is implemented without determining states of blocks. This poses a problem that when workpiece machining is resumed using program-resuming block data, a cutting edge of a machining tool is brought in contact with an already machined workpiece portion and a scratch is formed on the workpiece.